Artificial cellulose yarns produced by the stretch spinning process



Patented July 12, 1932 UNITED STATES PATENT, OFFICE ARTHUR ZART, 0F BARMEN-RITTEBSHAUSEN, AUGUST HARTMANN, OF DARREN, AND FRANZ HOELKESKAMP, OF BARMEN-RITTERSHAUSEN, GERMANY, ASSIGNORS TO AMERICAN BEMBERG CORPORATION, OF NEW YORK, N. Y.

ARTIFICIAL CELLULOSE YARNS PRODUCEDBY THE STRETCH SPINNING PROCESS No Drawing. Application filed December 18, 1928, Serial No. 326,891, and in Germany December 22, 1927.-

Our invention relates to artificial yarn produced from copper oxide ammonia cellulose by the stretch spinning process.

The subject of the invention is an artificial yarn composed of continuous practically endless individual filaments, the individual filaments having a titer of 1% deniers and below, the composed yarn having a tear resistance of over 220 ams per 100 deniers in the dry condition. l nd the wet condition, the same yarn has a tear resistance of over 140 grams per 100 deniers.

The technical advance over the known yarns lies in the increase of the tear resistance and therewith in a closer similarity to the resistance of the yarns produced from natural cellulose fibres. The formerlv known yarns of the kind described possessed for instance, when produced from copper oxide ammonia solution, as a rule, at the most, a tear resistance of 170 to 185 grams in the dry, and 85 to 95 grams in the wet condition.

The denier is a measure of the size of the threads which is usual in the silk industry. The number of deniers is equal to the weight in grams of .a thread of 9,000 meters in length.

The same individual filaments as are employed for the production of yarns may be used also for the production of fibres, so-

called staple fibres. The yarns produced therefrom possess also an increased resistance as compared with the yarns produced formerly from staple fibres.

The yarns according to the invention are produced from the artificial yarns obtained in known stretch spinnin devices, b known rocesses, by subjecting t e yarns w ile still in a plast1c condition to an additional stretching, that is, the threads are subjected after the precipitation and first stretchin and before the definite dissolving out 0 the solvent which is still contained in the threads and while the threads are still in a plastic condition, to a second considerable stretching. A second stretching between the spinning funnel and the wmding-on device is thus employed in addition to the first stretchmg in the spinning funnel. This second stretching must be so considerable that the desired increase of resistance takes place.

The silk may also be subsequently stretched 1n the skein, only it must take place while the silk is still in a sufliciently plastic condition.

by this subsequent treatment.

Usually, copper silk roduced by the stretch spinning process as, for example, when dry, a tear resistance of 160 grams. In

the wet condition, the tear resistance amounts to 85 grams. If the silk is subjected to a subsequent stretching of 60 per cent, for instance, tear resistances of 222 to 268 grams in the dry condition, and 146 to 183 grams in the wet condition, are obtained. The individual filaments of this yarn according to the invention have each the same essentially circular cross-section over their whole length.

The subse uent stretchin can be carried out so that tile threads, be ore the aciditying treatment, are allowed to run over two rollers,"the secdfid of which has the greater speed of rotation.

The tear tests on the ground of which the previous figures are established, were carried out with a fibre humidity of 11 per cent for the dry condition, and in the completely wet condition respectlvely at room temperature. In the tests, the so-called Schopper strength testing ap aratus or serimeter was used working on a ree piece of yarn 50 centimeters in length. The speed of tearing amounted to 50 centimeters per minute. The yarn titer was also ascertained with a fibre humidity of 11 per cent.\.

What we claim is A cuprammonium filament possessing a dry strength of from 220to 268 grams per we aflix our signa- 

